Present systems for weighing vehicles generally use a treadle system, that requires the truck or other vehicle being weighed to come to a complete stop so that the vibrations and bouncing of the treadle will damp out; otherwise, the recorded weight may be erroneous. This is an example of static weighing. Less time would be spent during weighing if the system were dynamic, i.e. if the vehicle could be weighed while in motion, as well as in stopped condition. Besides the need for a dynamic vehicle-weighing system, a need exists for a less expensive, as well as portable, vehicle-weighing system.
Dynamic vehicle-weighing systems are also known using four load cells, located at the corners of a plate called a bridge. This system is recessed into the pavement. While the system can measure weight dynamically, current technology requires speeds lower than 10 MPH to enable enough time duration for the weight on the bridge to stop the bouncing and vibration motions. The mechanical complexity of this measurement system is lower than that of treadle systems, but still high.
The two applications of greatest interest lie in weigh stations, where a fixed installation capable of measuring and recording the absolute weight of each axle while the vehicle is under way would be used, and in roadway locations, where a portable system easily applied across a roadway would register an overweight condition only. In other words, an alarm condition would be set at the appropriate weight, such that any vehicle passing over the weighing device and weighing in excess of the appropriate weight would trigger the alarm. Advantageously, such a system also could function in a static weighing mode as well.